Physical Description

A beaver can remain submerged underwater for long periods of time, and can close its nose and ears to prevent water entry. Its lips can close behind the four large incisor teeth, allowing a beaver to gnaw underwater without swallowing water. The underfur is dense and generally gray in color. The guard hair is long and coarse, ranging in color from yellow-brown to black, with red-brown as the most common coloration. The flattened tail is scaly, and nearly hairless. It is used as a rudder when swimming, a warning signal when slapped on the water, and a prop when sitting upright. Beavers have large, bright orange, front incisor teeth that grow continuously throughout their lives. The incisors are beveled, and sharpened through gnawing and chewing.  The only way to distinguish the sex of a beaver externally, unless it is a lactating female, is to feel for the presence of a baculum (a penis bone). Adult beavers typically weigh 35 to 50 pounds, with some reaching 70 to 85 pounds.